Samsung SGH-E390 - GSM900 Transmitter

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Flow Chart of Troubleshooting
9-24
9-13. GSM900 Transmitter
F100 Pin10
>= 20dBm
Resolder RFS100,C101,L100
TX ON (5Level)
Check F100
pin14 = H (2.68V)
pin13 = L
F100 pin15
>= 18dBm
U100 pin12
>= 18dBm
U102 pin36
>= -15dBm
U100 pin7
>= -11dBm
Check ANT Switch
control circuit
Change or Resolder F100
Resolder C111,L108.C114
Yes
Check U100
pin 2,3,4,5,6 OK?
Resolder or Change U100
Check +VBAT or PAM
control signal
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
U102 pin 1,2,3,4
>= 1V
Check & Resolder RFLO
signal, RF26MHz,
RF PSU Part
No
Yes
Yes
END
Check UCP200
Resolder U102
No
Check U102
pin5,8,19,31,35,39
>=2.7V
Resolder L112